Oxygen Not Included Guide

Scope and things to know first

Oxygen Not Included is a colony simulation about digging through an asteroid and maintaining Duplicants and their facilities. Adding rooms is only part of the task: materials must arrive, machines must run, and outputs need somewhere to go. Even a tidy base can lose essential services if materials or working time are insufficient.

1. This series covers normal play with the base game alone. It does not assume DLC asteroids, plants, or Bionic Duplicants. Numerical examples assume no consumption modifiers from traits or difficulty.
2. The latest released update confirmed during the source check was 744825. The free June 2026 update also changed the base game, so not owning DLC does not mean that older mechanics still apply.
3. Japanese is not listed among Steam's supported languages. Equipment names are also given in English. If you use a translation mod, separately check its terminology and supported game version.

Start with your current problem

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Choose one place where symptoms are already visible. You do not need to implement every guide at once.

Stop a collapse in this order: save lives, restore supplies, then expand

Assuming oxygen shortage is the only cause can hide a power outage or a trapped Duplicant. Pause first and select endangered Duplicants and stopped machines directly. Start with their status messages and trace backward along the route that was working before.

1. Immediate danger: check the route back to breathable air, ladders, and door access permissions. If construction blocked an exit, restore access first and cancel dangerous digging orders.
2. Continuing supplies: check oxygen equipment inputs, edible food, usable toilets, and generator fuel in that order. Fix why existing equipment stopped before building more.
3. Verify recovery: watch until oxygen arrives, Duplicants can eat, they wash their hands on the return route, and required machines can operate together. Finishing construction does not by itself complete recovery.
4. Expansion: remove one cause of recurrence. If supplies arrive late, shorten hauling routes before adding more digging. If power is insufficient, separate circuits to protect essential services.

The free June 2026 update changed suffocation behavior and added rescue and resuscitation for incapacitated Duplicants. Do not continue dangerous work on the assumption that rescue will succeed. First establish a route where rescuers can also breathe.

How one failure spreads to other facilities

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Inspect each system as a whole, including its outputs and Duplicant errands as well as its inputs.

Conditions to meet before moving on

Advancing by cycle number alone can overextend colonies with different terrain or resources. Meeting these conditions before adding people or equipment makes failures easier to diagnose.

1. Early-game milestone: everyone has a bed and a sanitary route, while food production and oxygen inputs are replenished during normal daily work.
2. Water expansion milestone: you know where water used for research, sanitation, and oxygen goes, and can manage polluted water separately from clean supplies.
3. Industrial milestone: essential services and industry have separate electrical loads, and hot equipment and liquids can be kept away from farms.
4. Population milestone: you can account for oxygen, food, and working time after adding a Duplicant, rather than relying only on current stocks. You do not have to accept someone every time candidates appear at the Printing Pod.

Handle heat by reducing it, moving it, and removing it

Heat accumulation matters early on, but saying that every machine produces heat or that heat can never be removed is inaccurate. Some buildings, such as Gas Pump, have zero building heat output. Thermo Aquatuner moves heat from liquid into itself, while Steam Turbine can remove heat from steam.

1. Reduce production: stop unnecessary generation or processing to reduce fuel use and machine operating time.
2. Move heat: transfer it into coolant, while also providing somewhere to cool that liquid.
3. Remove heat: use equipment such as Steam Turbine from the midgame onward. Include cooling for the turbine itself and its operating conditions in the design.

Transferring heat into a cold biome uses it as temporary heat storage. It does not stay cold indefinitely.